/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package javax.servlet;

import java.util.Enumeration;



/**
 * https://securitit.blog.csdn.net/article/details/108031554
 *
 * 对于ServletConfig，按照字面意思理解来看，是Servlet的配置类。实际情况也的确如此，ServletConfig在服务中可以获得Servlet的配置信息
 *
 * Servlet配置对象.用于Servlet容器在Servlet初始化期间传递配置.
 *
 * ServletConfig的API定义十分简单，一共提供了4个方法：
 * getServletName()、getInitParameter(String name)、getInitParameterNames()用于获取Servlet的配置信息（无论是2.x版本通过web.xml配置还是3.x版本通过编程式方式配置）。
 * getServletContext用户获取Servlet容器的上下文，为Servlet中获取ServletContext提供了通道。
 *
 *
 * A servlet configuration object used by a servlet container
 * to pass information to a servlet during initialization. 
 *
 */
 
public interface ServletConfig {
    

    /**
     * 获取Servlet名称.
     *
     * Returns the name of this servlet instance.
     * The name may be provided via server administration, assigned in the 
     * web application deployment descriptor, or for an unregistered (and thus
     * unnamed) servlet instance it will be the servlet's class name.
     *
     * @return		the name of the servlet instance
     *
     *
     *
     */

    public String getServletName();

    /**
     * 获取当前Servlet上下文对象ServletContext.
     *
     * Returns a reference to the {@link ServletContext} in which the caller
     * is executing.
     *
     *
     * @return		a {@link ServletContext} object, used
     *			by the caller to interact with its servlet 
     *                  container
     * 
     * @see		ServletContext
     *
     */

    public ServletContext getServletContext();
    
    /**
     * 根据参数名获取Servlet初始化参数.
     *
     * Returns a <code>String</code> containing the value of the
     * named initialization parameter, or <code>null</code> if 
     * the parameter does not exist.
     *
     * @param name	a <code>String</code> specifying the name
     *			of the initialization parameter
     *
     * @return		a <code>String</code> containing the value 
     *			of the initialization parameter
     *
     */

    public String getInitParameter(String name);


    /**
     * 获取所有Servlet初始化参数.
     *
     * Returns the names of the servlet's initialization parameters
     * as an <code>Enumeration</code> of <code>String</code> objects, 
     * or an empty <code>Enumeration</code> if the servlet has
     * no initialization parameters.
     *
     * @return		an <code>Enumeration</code> of <code>String</code> 
     *			objects containing the names of the servlet's 
     *			initialization parameters
     *
     *
     *
     */

    public Enumeration getInitParameterNames();


}
